+, * These procedures return the sum or product of their arguments.

+, * These procedures return the sum or product of their arguments.

-, / With two or more arguments, these procedures return the difference or quotient of their arguments, associating to the left. With one argument, however, they return the additive or multiplicative inverse of their argument. It is an error if any argument of / other than the first is an exact zero. If the first argument is an exact zero, an implementation may return an exact zero unless one of the other arguments is a NaN.

=, <, >, <=, >= These procedures return #t if their arguments are (respectively): equal, monotonically increasing, monotonically decreasing, monotonically non-decreasing, or monotonically non-increasing, and #f otherwise. If any of the arguments are +nan.0, all the predicates return #f. They do not distinguish between inexact zero and inexact negative zero. These predicates are transitive. Note: While it is not an error to compare inexact numbers using these predicates, the results are unreliable because a small inaccuracy can affect the result; this is especially true of = and zero?. When in doubt, consult a numerical analyst.

The abs procedure returns the absolute value of its argument.

floor, ceiling, truncate, round These procedures return integers. The floor procedure returns the largest integer not larger than x. The ceiling procedure returns the smallest integer not smaller than x, truncate returns the integer closest to x whose absolute value is not larger than the absolute value of x, and round returns the closest integer to x, rounding to even when x is halfway between two integers. Rationale: The round procedure rounds to even for consistency with the default rounding mode specified by the IEEE 754 IEEE floating-point standard. Note: If the argument to one of these procedures is inexact, then the result will also be inexact. If an exact value is needed, the result can be passed to the exact procedure. If the argument is infinite or a NaN, then it is returned.

The procedure exact returns an exact representation of z. The value returned is the exact number that is numerically closest to the argument. For exact arguments, the result is the same as the argument. For inexact nonintegral real arguments, the implementation may return a rational approximation, or may report an implementation violation. For inexact complex arguments, the result is a complex number whose real and imaginary parts are the result of applying exact to the real and imaginary parts of the argument, respectively. If an inexact argument has no reasonably close exact equivalent, (in the sense of =), then a violation of an implementation restriction may be reported.

Returns #t if z is both exact and an integer; otherwise returns #f.

exact?, inexact? These numerical predicates provide tests for the exactness of a quantity. For any Scheme number, precisely one of these predicates is true.

Returns z1 raised to the power z2.